Device and method for generating bandwidth-adjustable flat optical frequency comb based on selective filtering

Abstract

The present application relates to the field of optical frequency comb technology, and more particularly to a device and method for generating a bandwidth-adjustable, flat optical frequency comb based on selective filtering. The device comprises: a pump light source and a nonlinear medium; a first tunable reflective filter and a second tunable reflective filter. The laser light generated by the pump light source is coupled into the nonlinear medium using the first tunable reflective filter, or is coupled into the nonlinear medium using an evanescent field, and is output through the second tunable reflective filter to generate an optical frequency comb. A control unit is configured to tune the intersection of the reflection passbands of the first tunable reflective filter and the second tunable reflective filter to adjust the optical frequency comb bandwidth to a target optical frequency comb bandwidth. This solves the problems in the related art of the complexity and high cost of implementing a bandwidth-controllable, broadband optical frequency comb and how to achieve a simple and easily adjustable bandwidth-controllable, broadband optical frequency comb light source.

Description

Technical Field

[0001] The present application relates to the field of optical frequency comb technology, and in particular to a device and method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering. Background Art

[0002] Since its introduction, optical frequency combs, also known as optical frequency combs, have been considered a key solution for multi-wavelength light sources. Due to their large number of wavelengths and good coherence between them, they hold broad application prospects in fields such as fiber-optic communications and lidar.

[0003] In related technologies, optical frequency combs can be generated by mode-locked lasers or cascaded electro-optical modulators. The cascaded electro-optical modulator scheme can achieve a bandwidth-adjustable optical frequency comb by adjusting the microwave power applied to the modulator. However, due to the limited power that a single modulator can withstand, expanding the bandwidth requires multiple modulators and a high-quality microwave source. Microcavity Kerr optical frequency combs based on third-order nonlinearity have attracted more attention due to their large number of comb teeth and small device size. The basic principle is that when light propagates within a resonant cavity, the refractive index of the dielectric waveguide is modulated by the light intensity due to the presence of third-order nonlinear effects, affecting the group velocity. When the effects of the nonlinear effect and the dispersion effect on the group velocity are balanced, and the cavity loss and coupling gain are balanced, optical pulses can be formed in the time domain, which manifests as equally spaced comb teeth in the frequency domain. The comb tooth range of an optical frequency comb generally depends on the magnitude of the total dispersion of the waveguide. Generally, smaller dispersion can produce a wider spectrum.

[0004] However, in the related art, the implementation structure of the bandwidth-controllable broadband optical frequency comb light source is complex and the cost is high. Therefore, how to realize a simple and easy-to-adjust bandwidth-controllable broadband optical frequency comb light source remains an unresolved problem. Summary of the Invention

[0005] The present application provides a device and method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering to address the problems in related technologies such as the complexity and high cost of implementing a bandwidth-controllable broadband optical frequency comb and the difficulty in achieving a simple and easily adjustable bandwidth-controllable broadband optical frequency comb light source.

[0006] A first aspect of the present application provides a bandwidth-adjustable flat optical frequency comb generator based on selective filtering, comprising: a pump light source and a nonlinear medium; a first adjustable reflective filter and a second adjustable reflective filter, wherein the laser generated by the pump light source is coupled into the nonlinear medium using the first adjustable reflective filter, or is coupled into the nonlinear medium by evanescent field, and is output through the second adjustable reflective filter to generate an optical frequency comb; and a control unit is configured to tune the intersection of the reflection passbands of the first adjustable reflective filter and the second adjustable reflective filter to adjust the optical frequency comb bandwidth of the optical frequency comb to reach a target optical frequency comb bandwidth.

[0007] Optionally, in one embodiment of the present application, both the first tunable reflective filter and the second tunable reflective filter may be, but are not limited to, photonic crystal grating structures.

[0008] Optionally, in one embodiment of the present application, the grating in the photonic crystal grating structure is obtained by preset period design and preset refractive index modulation to meet the target requirements of at least one of reflection passband bandwidth, reflection passband center frequency, dispersion, and delay.

[0009] Optionally, in one embodiment of the present application, the formula for obtaining the reflection passband center frequency may be, but is not limited to,:

[0010]

[0011] Among them, k T is the grating thermo-optical coefficient, Λ is the grating period, is the effective refractive index of the grating region when the temperature is T0, ΔT is the temperature change of the grating region when the electrodes are heated, and c is the speed of light.

[0012] Optionally, in one embodiment of the present application, the method further includes: a coupler, wherein the coupler is arranged between the pump light source and the nonlinear medium.

[0013] Optionally, in one embodiment of the present application, the material of the nonlinear medium may be, but is not limited to, a material having third-order nonlinearity.

[0014] A second aspect of the present application provides a method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering, which is applied to the bandwidth-adjustable flat optical frequency comb generating device based on selective filtering as described above, wherein the method includes the following steps: laser light generated by a pump light source is coupled into a nonlinear medium using a first adjustable reflective filter, or is coupled into the nonlinear medium by evanescent field, so as to be output through a second adjustable reflective filter to generate an optical frequency comb; and the intersection of the reflection passbands of the first adjustable reflective filter and the second adjustable reflective filter is tuned to adjust the optical frequency comb bandwidth of the optical frequency comb to reach a target optical frequency comb bandwidth.

[0015] Optionally, in one embodiment of the present application, both the first tunable reflective filter and the second tunable reflective filter may be, but are not limited to, photonic crystal grating structures.

[0016] Optionally, in one embodiment of the present application, the grating in the photonic crystal grating structure is obtained by preset period design and preset refractive index modulation to meet the target requirements of at least one of reflection passband bandwidth, reflection passband center frequency, dispersion, and delay.

[0017] Optionally, in one embodiment of the present application, the formula for obtaining the reflection passband center frequency may be, but is not limited to,:

[0018]

[0019] Among them, k T is the grating thermo-optical coefficient, Λ is the grating period, is the effective refractive index of the grating region when the temperature is T0, ΔT is the temperature change of the grating region when the electrodes are heated, and c is the speed of light.

[0020] Optionally, in one embodiment of the present application, the material of the nonlinear medium may be, but is not limited to, a material having third-order nonlinearity.

[0021] An embodiment of the third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering as described in the above embodiment.

[0022] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the above-mentioned method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering.

[0023] The fifth aspect of the present application provides a computer program product, including a computer program, which, when executed, implements the above-mentioned method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering.

[0024] The laser light generated by the pump light source in the embodiments of the present application can be coupled into a nonlinear medium using a first tunable reflective filter, or injected into a nonlinear medium using evanescent field coupling, and output through a second tunable reflective filter to generate an optical frequency comb. The control unit then tunes the intersection of the reflection passbands of the first and second tunable reflective filters to adjust the optical frequency comb bandwidth to a target optical frequency comb bandwidth. This solves the problems in related technologies such as the complexity and high cost of implementing bandwidth-controllable broadband optical frequency combs and the difficulty in achieving a simple and easily adjustable bandwidth-controllable broadband optical frequency comb source.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 Schematic diagram of a block diagram of a device for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering according to an embodiment of the present application;

[0028] Figure 2 A schematic diagram of a mechanism for achieving bandwidth control according to an embodiment of the present application;

[0029] Figure 3 A schematic block diagram of the intersection range of three different ideal Gaussian passbands provided according to one embodiment of the present application;

[0030] Figure 4 A schematic block diagram of a mode-locked optical comb generated by a resonant cavity composed of different reflective gratings according to one embodiment of the present application;

[0031] Figure 5 Flowchart of a method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering according to an embodiment of the present application;

[0032] Figure 6 A schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] The following describes, with reference to the accompanying drawings, a device and method for generating a bandwidth-adjustable, flattened optical frequency comb based on selective filtering according to an embodiment of the present application. To address the issues mentioned in the background art above, such as the complexity and high cost of implementing a bandwidth-adjustable, broadband optical frequency comb, and the difficulty in achieving a simple and easily adjustable bandwidth-adjustable, broadband optical frequency comb source, the present application provides a device and method for generating a bandwidth-adjustable, flattened optical frequency comb based on selective filtering. In this device, laser light generated by a pump light source can be coupled into a nonlinear medium using a first adjustable reflective filter, or injected into the nonlinear medium using an evanescent field coupling, and then output through a second adjustable reflective filter to generate an optical frequency comb. The control unit then tunes the intersection of the reflection passbands of the first and second adjustable reflective filters to adjust the optical frequency comb bandwidth to a target optical frequency comb bandwidth. This solves the problems in the related art, such as the complexity and high cost of implementing a bandwidth-adjustable, broadband optical frequency comb, and the difficulty in achieving a simple and easily adjustable bandwidth-adjustable, broadband optical frequency comb source.

[0035] Specifically, Figure 1Schematic diagram of a block diagram of a device for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering according to an embodiment of the present application.

[0036] like Figure 1 As shown, the bandwidth-adjustable flat optical frequency comb generating device 10 based on selective filtering includes: a pump light source 100, a nonlinear medium 200, an adjustable reflective filter (the adjustable reflective filter may include but is not limited to a first adjustable reflective filter 301 and a second adjustable reflective filter 302) and a control unit 400.

[0037] Among them, the pump light source 100.

[0038] It is understandable that the pump light source 100 in the embodiment of the present application may be, but is not limited to, a tunable laser, which may be, but is not limited to, generating single-frequency continuous light, and is typically a fiber laser or a distributed feedback laser diode.

[0039] It should be noted that in the embodiment of the present application, the pump light source 100 may also be other types of lasers, such as a pulsed laser, etc., and the present application does not impose any specific restrictions.

[0040] The pump light source 100 is connected to the optical chip input port by directly connecting the chip or using a lens fiber, and the system output is coupled from the output port through the lens fiber. Other coupling schemes to achieve similar effects are also possible. The specific settings can be made by technicians in this field according to actual conditions, and this application does not impose specific restrictions.

[0041] Furthermore, in the embodiment of the present application, the energy of the pump light source 100 accumulates in the resonant cavity composed of two tunable reflective filters and the nonlinear medium 200 to excite nonlinear effects. Since the tunable reflective filters have high reflectivity, the resonant cavity can have a high Q value, which is conducive to the excitation of nonlinear effects and the generation of optical frequency combs. Furthermore, the light output by the tunable laser of the embodiment of the present application can be transmitted into the above-mentioned resonant cavity. Related art shows that when the resonant frequency of the resonant cavity is satisfied, the intracavity light field ψ can be given by the normalized Schrödinger equation, which can be expressed as, but not limited to:

[0042]

[0043] Where δ is the frequency detuning, β m is the m-order dispersion coefficient, S is the normalized light source, α is the intracavity loss, and L is the cavity length.

[0044] Furthermore, due to the special structure of the embodiment of the present application, the above equation can be rewritten as follows through deduction:

[0045]

[0046] in, is the transfer function after R1R2 normalization.

[0047] In the embodiment of the present application, when the conditions for generating an optical comb are met, the light field in the cavity will appear as a flat optical comb with limited bandwidth. Therefore, the embodiment of the present application can achieve optical comb bandwidth control by adjusting the reflection parameter η.

[0048] Nonlinear medium 200. The material of the nonlinear medium 200 may be, but is not limited to, a material having third-order nonlinearity.

[0049] It is understood that the material of the nonlinear medium 200 in the embodiment of the present application can be, but is not limited to, a material exhibiting third-order nonlinearity. Commonly used materials include Si3N4, AlN, and LiNbO3, which have low optical loss and high nonlinear coefficients and facilitate the generation of optical frequency combs. The specific configuration can be determined by those skilled in the art based on practical circumstances and is not specifically limited in this application.

[0050] In addition, in the embodiment of the present application, in order to make the nonlinear medium 200 reach the required dispersion value, a straight waveguide structure is usually used. However, for the unique parameters of different materials, special structures help to better balance the relationship between dispersion and loss. Therefore, the embodiment of the present application is not limited to the nonlinear medium 200 using a straight waveguide structure, and nonlinear media 200 with other structures can also be used. The specific settings can be made by technicians in this field according to actual conditions, and this application does not impose specific restrictions.

[0051] The first tunable reflective filter 301 and the second tunable reflective filter 302 are configured such that the laser light generated by the pump light source 100 is coupled into the nonlinear medium 200 using the first tunable reflective filter 301 or is coupled into the nonlinear medium 200 using the evanescent field, and is outputted through the second tunable reflective filter 302 to generate an optical frequency comb.

[0052] It can be understood that the first tunable reflective filter 301 and the second tunable reflective filter 302 are devices capable of reflecting light waves within a specific frequency bandwidth, and this application does not impose any specific limitations thereon.

[0053] As a possible implementation method, the embodiments of the present application can control the bandwidth of the optical frequency comb by tuning the intersection of the reflection passbands of the first tunable reflective filter 301 and the second tunable reflective filter 302. When the passbands of these two tunable reflective filters are sufficiently large, an optical frequency comb with controllable bandwidth can be generated within the tuning range.

[0054] For example, the first adjustable reflective filter 301 and the second adjustable reflective filter 302 of the embodiment of the present application have a certain reflection passband such as Figure 2As shown in (a), the reflection passband can be adjusted by the control unit 400. When the reflection spectra of the two filters intersect in frequency, as shown in Figure 2 (b) The intersection bandwidth Δf is the bandwidth of the actual resonant cavity.

[0055] Optionally, in one embodiment of the present application, both the first tunable reflective filter 301 and the second tunable reflective filter 302 may be, but are not limited to, photonic crystal grating structures. The gratings in the photonic crystal grating structure are obtained by designing a preset period and modulating a preset refractive index to meet at least one of the target requirements for reflection passband bandwidth, reflection passband center frequency, dispersion, and delay.

[0056] It can be understood that the first adjustable reflective filter 301 and the second adjustable reflective filter 302 in the embodiment of the present application can be, but are not limited to, photonic crystal grating structures. The grating is obtained by a certain period design and a certain refractive index modulation to meet the target requirements such as reflection passband bandwidth, reflection passband center frequency, dispersion, and delay.

[0057] Among them, the certain period and the certain refractive index can be set by technicians in this field according to actual conditions, and this application does not impose any specific restrictions.

[0058] Furthermore, in the embodiment of the present application, the grating and the nonlinear medium 200 are prepared on the aforementioned material platform through a photonic integration process. After the processing is completed, an optical chip with input and output ports is formed. The laser can enter the optical chip through the input port and directly couple through the filter, such as Figure 1 (a), or through evanescent field coupling, as shown in Figure 1 (b) Enter the nonlinear medium 200.

[0059] Optionally, in one embodiment of the present application, a formula for obtaining the reflection passband center frequency may be, but is not limited to,:

[0060]

[0061] Among them, k T is the grating thermo-optical coefficient, Λ is the grating period, is the effective refractive index of the grating region when the temperature is T0, ΔT is the temperature change of the grating region when the electrodes are heated, and c is the speed of light.

[0062] As a possible implementation method, the embodiment of the present application assumes that the grating thermo-optical coefficient k T =dn / dT, given the grating period Λ, the formula for obtaining the grating reflection passband center frequency can be, but is not limited to,:

[0063]

[0064] Among them, k T is the grating thermo-optical coefficient, Λ is the grating period, is the effective refractive index of the grating region when the temperature is T0, ΔT is the temperature change of the grating region when the electrodes are heated, and c is the speed of light.

[0065] In addition, the effective refractive index of the embodiment of the present application is determined by the refractive index of the material and the waveguide structure. Therefore, the embodiment of the present application can achieve the movement of the reflection passband center by changing the temperature. Figure 3 As shown, the embodiment of the present application shows the Gaussian passband of the grating, wherein the passbands of these three groups of gratings can correspond to Δf=20THz, 25THz, and 30THz respectively.

[0066] The control unit 400 is configured to tune the intersection of the reflection passbands of the first tunable reflective filter 301 and the second tunable reflective filter 302 to adjust the optical frequency comb bandwidth to reach a target optical frequency comb bandwidth.

[0067] As a possible implementation method, the control unit 400 of the embodiment of the present application can be used to tune the intersection of the reflection passbands of the first tunable reflective filter 301 and the second tunable reflective filter 302, thereby adjusting the optical frequency comb bandwidth of the optical frequency comb to reach the target optical frequency comb bandwidth.

[0068] For example, in an embodiment of the present application, the reflection functions of the two adjustable reflective filters that change with frequency are set to R1(η, f) and R2(η, f), respectively. By adjusting R1(η, f) and R2(η, f) by the control unit 400, the reflection band can be changed to achieve the target optical frequency comb bandwidth.

[0069] In the embodiment of the present application, when other effects are not considered, the one-way transfer function of the resonant cavity formed by the first adjustable reflective filter 301 and the second adjustable reflective filter 302 is R1R2.

[0070] Optionally, in one embodiment of the present application, it further includes: a fiber coupler, which is arranged between the pump light source 100 and the nonlinear medium 200.

[0071] In some embodiments, the present invention is implemented using a fiber optic system. In this case, the nonlinear medium 200 in the system is an optical fiber, and the tunable reflective filter is a fiber Bragg grating (FBG). System dispersion is controlled by connecting a specialized fiber with normal dispersion. Highly nonlinear fiber can also be used to further enhance the nonlinearity in the system, reducing the power required to generate the optical frequency comb. For direct coupling, the laser output of the pump source 100 is directly connected to the fiber Bragg grating (FBG). For evanescent field coupling, energy coupling between the laser from the pump source 100 and the nonlinear medium 200 is achieved through a fiber coupler.

[0072] The working principle of the bandwidth-adjustable flat optical frequency comb generating device based on selective filtering proposed in the embodiment of the present application is described in detail below with reference to a specific embodiment.

[0073] Example 1:

[0074] The embodiments of the present application describe a solution for generating a flat and tunable optical comb using a photonic crystal grating structure as a tunable reflective filter.

[0075] It is understood by those skilled in the art that the refractive index of the material used in the embodiment of the present application is affected by the thermo-optic effect, electro-optic effect, piezoelectric effect, etc. Here, the thermo-optic effect is taken as an example. Assuming that the grating thermo-optic coefficient k T =dn / dT, given the grating period Λ, the formula for obtaining the grating reflection passband center frequency is shown above, Figure 3 The Gaussian passband of the grating is shown, and the passbands of the three groups of gratings correspond to Δf = 20 THz, 25 THz, and 30 THz respectively.

[0076] Furthermore, in the embodiment of the present application, by adjusting the reflection passband of the two gratings, the optical comb will be generated in the common reflection passband. Using the equations derived above to perform numerical simulation, by slowly adjusting the detuning amount δ, soliton generation and stabilization can be achieved, wherein, in the embodiment of the present application, Figure 4 The simulation results of the optical comb are shown in Figure 1. The three curves correspond to the three groups of gratings with passband widths shown above. Figure 4 In the figure, the comb teeth with the center raised are the pump energy, and the remaining envelopes record the energy of the comb teeth at each frequency. When adjusting the different grating passband overlap ranges, the optical comb bandwidth is different. At the same time, although the overall power of the optical comb changes, the flatness remains good. Taking the wide passband result as an example, within the 20THz frequency range, the power difference is less than 1dB. It can be seen that the embodiment of the present application can generate an optical comb with a flat spectrum, and at the same time, by adjusting the filter passband range, it is possible to achieve the generation of optical frequency combs with different bandwidths.

[0077] According to the selective filtering-based bandwidth-adjustable flattened optical frequency comb generator proposed in the embodiments of this application, the laser light generated by the pump light source can be coupled into a nonlinear medium using a first adjustable reflective filter, or injected into a nonlinear medium using evanescent field coupling, and output through a second adjustable reflective filter to generate an optical frequency comb. The control unit then tunes the intersection of the reflection passbands of the first and second adjustable reflective filters to adjust the optical frequency comb bandwidth to the target optical frequency comb bandwidth. This solves the problems in related technologies such as the complexity and high cost of implementing bandwidth-controllable broadband optical frequency combs and the need to realize a simple and easily adjustable bandwidth-controllable broadband optical frequency comb source.

[0078] Next, a method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0079] like Figure 5 As shown, the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering is applied to the apparatus for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering as shown above, wherein the method comprises the following steps:

[0080] In step S501 , laser light generated by a pump light source is coupled into a nonlinear medium using a first tunable reflective filter, or is coupled into a nonlinear medium using an evanescent field, and is output through a second tunable reflective filter to generate an optical frequency comb.

[0081] In step S502 , the reflection passband intersection of the first tunable reflective filter and the second tunable reflective filter is tuned to adjust the optical frequency comb bandwidth of the optical frequency comb to reach the target optical frequency comb bandwidth.

[0082] Optionally, in one embodiment of the present application, both the first tunable reflective filter and the second tunable reflective filter may be, but are not limited to, photonic crystal grating structures.

[0083] Optionally, in one embodiment of the present application, the grating in the photonic crystal grating structure is obtained by preset period design and preset refractive index modulation to meet the target requirements of at least one of the reflection passband bandwidth, reflection passband center frequency, dispersion, and delay.

[0084] Optionally, in one embodiment of the present application, a formula for obtaining the reflection passband center frequency may be, but is not limited to,:

[0085]

[0086] Among them, k T is the grating thermo-optical coefficient, Λ is the grating period, is the effective refractive index of the grating region when the temperature is T0, ΔT is the temperature change of the grating region when the electrodes are heated, and c is the speed of light.

[0087] Optionally, in one embodiment of the present application, the material of the nonlinear medium may be, but is not limited to, a material having third-order nonlinearity.

[0088] It should be noted that the aforementioned explanation of the embodiment of the apparatus for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering is also applicable to the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering in this embodiment, and will not be repeated here.

[0089] According to the selective filtering-based bandwidth-adjustable flat optical frequency comb generation method proposed in the embodiments of this application, the laser light generated by the pump light source can be coupled into a nonlinear medium using a first tunable reflective filter, or injected into a nonlinear medium using evanescent field coupling, and output through a second tunable reflective filter to generate an optical frequency comb. The control unit then tunes the intersection of the reflection passbands of the first and second tunable reflective filters to adjust the optical frequency comb bandwidth to the target optical frequency comb bandwidth. This solves the problems in related technologies such as the complexity and high cost of implementing bandwidth-controllable broadband optical frequency combs and the difficulty in achieving a simple and easily adjustable bandwidth-controllable broadband optical frequency comb source.

[0090] Figure 6 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. The electronic device may include:

[0091] A memory 601 , a processor 602 , and a computer program stored in the memory 601 and executable on the processor 602 .

[0092] When the processor 602 executes the program, the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering provided in the above embodiment is implemented.

[0093] Furthermore, the electronic device further includes:

[0094] The communication interface 603 is used for communication between the memory 601 and the processor 602 .

[0095] The memory 601 is used to store computer programs that can be run on the processor 602 .

[0096] The memory 601 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0097] If the memory 601, processor 602, and communication interface 603 are implemented independently, the communication interface 603, memory 601, and processor 602 can be interconnected via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0098] Optionally, in a specific implementation, if the memory 601, the processor 602 and the communication interface 603 are integrated on a chip, the memory 601, the processor 602 and the communication interface 603 can communicate with each other through an internal interface.

[0099] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0100] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering.

[0101] An embodiment of the present application further provides a computer program product, including a computer program, which, when executed, implements the above-mentioned method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering.

[0102] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0103] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0104] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0105] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing it in other suitable ways as necessary, and then storing it in a computer memory.

[0106] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented using hardware, as in another embodiment, it can be implemented using any one or a combination of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0107] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0108] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0109] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A device for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering, characterized in that: include: Pump light sources and nonlinear media; a first tunable reflective filter and a second tunable reflective filter, wherein the laser light generated by the pump light source is coupled into the nonlinear medium using the first tunable reflective filter, or is coupled into the nonlinear medium using an evanescent field, and is output through the second tunable reflective filter to generate an optical frequency comb; A control unit is configured to tune the intersection of reflection passbands of the first tunable reflective filter and the second tunable reflective filter to adjust the optical frequency comb bandwidth of the optical frequency comb to reach a target optical frequency comb bandwidth.

2. The device according to claim 1, characterized in that The first tunable reflective filter and the second tunable reflective filter both have photonic crystal grating structures.

3. The device according to claim 2, characterized in that The grating in the photonic crystal grating structure is obtained by preset period design and preset refractive index modulation to meet at least one target requirement of reflection passband bandwidth, reflection passband center frequency, dispersion, and delay.

4. The device according to claim 3, characterized in that The formula for obtaining the reflection passband center frequency is: Among them, k T is the grating thermo-optical coefficient, Λ is the grating period, is the effective refractive index of the grating region when the temperature is T0, ΔT is the temperature change of the grating region when the electrodes are heated, and c is the speed of light.

5. The device according to claim 1, characterized in that Also includes: An optical fiber coupler is provided between the pump light source and the nonlinear medium.

6. The device according to claim 1, characterized in that The material of the nonlinear medium is a material with third-order nonlinearity.

7. A method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering, characterized in that: The method is applied to the selective filtering-based bandwidth-adjustable flat optical frequency comb generator according to any one of claims 1 to 6, wherein the method comprises the following steps: The laser light generated by the pump light source is coupled into the nonlinear medium using a first tunable reflective filter, or is coupled into the nonlinear medium using an evanescent field, and is output through a second tunable reflective filter to generate an optical frequency comb; The reflection passband intersection of the first tunable reflective filter and the second tunable reflective filter is tuned to adjust the optical frequency comb bandwidth of the optical frequency comb to reach a target optical frequency comb bandwidth.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering as claimed in claim 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering as claimed in claim 7.

10. A computer program product, characterized in that The invention comprises a computer program, which is used to implement the method for generating a bandwidth-adjustable flat optical frequency comb based on selective filtering as claimed in claim 7 when the program is executed.

Images